Swiss medical firm Roche is being investigated after concerns were raised over the incorrect reporting of drug side-effects.

Reuters reports that European drug regulator the European Medicines Agency (EMA) -- the equivalent of the U.S. Food and Drug Administration (FDA) -- is investigating Roche for its alleged failure to properly report the impact drugs may have on patients.

The world's largest developer of cancer medication may have improperly reported tens of thousands of potential side-effects. If found guilty, the firm could be fined up to 5 percent of its annual turnover, which was roughly $13.8 billion in 2011. The EMA said:

"The agency will report the outcome of its investigation to the European Commission who may impose fines or periodic penalty payments... if it finds that Roche has committed an infringement of its obligations."

During a routine inspection in June, the agency found that the firm failed to assess up to 80,000 cases of potential drug reactions. Approximately 15,000 deaths may have been connected to the drugs, or may have been the result of natural illness progression.

Roche told the publication that it is cooperating with the investigation, and so far, no safety concerns have been discovered.